Kursk was in 1943. One way to look at the Russo-German war is to think of 1942 as a wash. The Germans ended up roughly where they started. Even if the Germans had won at Kursk, where would they have gone? They surely didn't have the ability to get to the Volga again.
In 1942, the whole western theater was a side show for the Germans. The American and British contribution in 1943 did allow the Soviets to really start kicking the Krauts butt. That said, the war would have dragged on for many more years without the Allies pushing from the west.
Again, though this presupposes that such advances as the jet weren't going to totally overwhelm the Russians tactically, which they would have. I don't think Hitler could have re-taken MOscow, but Stalin was already dispatching peace emmissaries as late as 1943 (!!), indicating that certainly HE was not all that confident, even WITH American support.